• 2018-2019: Assistant Secretary for Indo-Pacific Security Affairs, Department for Defense, USA

• 2003-2005: Deputy Assistant Secretary for East Asian and Pacific Affairs, Department of State, USA

• 2001-2003: Chief of Staff and Senior Policy Advisor to Deputy Secretary of State Richard Armitage, USA

• 1999: Special Assistant to the Chairman of the Joint Chiefs of Staff, USA 

• 1997-1998: Senior Country Director for the PRC, Taiwan and Mongolia, Office of the Secretary of Defense, USA

• 1996-1997: Attaché at U.S. Embassy Beijing and U.S. Embassy Ulaanbaatar, USA

• 1995-1997: Assistant Country Director for the PRC, Taiwan and Mongolia, Office of the Secretary of Defense, USA

• 1995: Officer, the Office of Counter Proliferation Policy, Office of the Secretary of Defense, USA

• 1994: Officer, the Commission on Roles and Missions of the Armed Forces, Office of the Secretary of Defense, USA

• 1991-2000: Navy Reserved Officer, USA

• 1989-1991: Navy Intelligence Officer, USA